package com.example.springboot.common;

import cn.hutool.core.util.StrUtil;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.example.springboot.entity.User;
import com.example.springboot.exception.ServiceException;
import com.example.springboot.mapper.UserMapper;
import jakarta.annotation.Resource;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.asm.Handle;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

public class JwtInterceptor implements HandlerInterceptor {
    @Resource
    private UserMapper userMapper;
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler){
        String token = request.getHeader("token");//header里面传过来的参数
        // 验证token
        if(StrUtil.isBlank(token)){
            token=request.getParameter("token");//url参数 ?token=xxxx
        }
        if (handler instanceof HandlerMethod){
            AuthAccess authAccess = ((HandlerMethod) handler).getMethodAnnotation(AuthAccess.class);
            if (authAccess!=null){
                return true;
            }
        }
        //执行认证
        if(StrUtil.isBlank(token)){
            throw new ServiceException("401","请登录");
        }
        // 获取token中的userid
        String userId;
        try {
            userId = JWT.decode(token).getAudience().get(0);//JWT.decode(token)解码 jwt token
        }catch (JWTDecodeException j){
            throw new ServiceException("401","请登录");
        }
        // 根据token中的userid查询数据库
        User user=userMapper.selectById(Integer.valueOf(userId));
        if(user==null){
            throw new ServiceException("401","请登录");
        }
        //通过用户密码加密之后生成一个验证器
        JWTVerifier verifier = JWT.require(Algorithm.HMAC256(user.getPassword())).build();
        try {
            verifier.verify(token);
        }catch (JWTVerificationException j){
            throw new ServiceException("401","请登录");
        }
        return true;
    }
}
